Perseverative Cognition (PC), i.e. intrusive, uncontrollable, repetitive thoughts regarding past stressful events or feared future outcomes, plays a crucial role in stress recovery. These PCs are associated with imbalances in the heart-brain nexus, reflected in reduced parasympathetic control (over sympathetic reactivity) and reduced prefrontal control (over limbic reactivity). Research has shown that physical exercise—regular and acute— reduces the duration of negative mood during recovery, possibly via the influence of this heart- brain nexus and associated PC. The aim of this project is to investigate the psychophysiological working mechanisms underlying PC during stress recovery, using physical exercise to increase parasympathetic (vagal) tone, and prefrontal neuromodulation to boost this heart-brain nexus. We propose well-powered, scientifically sound studies, both in a well-controlled lab setting (work package 1 & 2) as in daily life (work package 3) of caregivers who are facing chronic stress, to investigate PC in the context of high stress. We will investigate how physiological factors (metrics of parasympathetic activity) and heart-brain couplings contribute to individual differences in bouncing back from PC. We aim to take an interdisciplinary approach, where affective neuroscience meets intervention programs.